Award-winning author Bradley Steffens introduces Ibn al-Haytham in this first full biography ever written about him. Though not a household name as far as the history of science goes, with his major contributions going largely unnoticed and uncredited, Ibn al-Haytham, who lived a thousand years ago, is finally being recognised as the world's first true scientist. Centuries before better-known researchers such as Roger Bacon, Leonardo da Vinci, and Galileo Galilei were born, Ibn al-Haytham investigated eyesight and the propagation of light in a profound manner, the likes of which had never before been fully utilised, and documented his findings in his magnum opus Book of Optics. By systematically using experiments to test his hypotheses, Ibn al-Haytham changed the course of human history, giving humankind a new and effective way of establishing facts about the natural world -- an approach known today as the scientific method.